[Novel approach to parathyroid adenoma: minimally invasive, focused, scan guided parathyroidectomy--experience from...

Traditionally, the surgical approach to parathyroid adenoma included formal bilateral neck exploration, inspection and evaluation of all four glands. Recently, following progress in the precision of pre-operative localization by sonography and scintigraphy and the availability of a real time PTH assay, focused, minimally invasive approaches to the removal of a single adenoma were proposed. We review our experience in the first 100 cases.

After localization of the suspected adenoma by TC-99m-MIBI scintigraphy and neck sonography, a second scan was performed just before surgery and the presumed site was marked on the patients skin. Under general anesthesia, via a limited incision, the suspected adenoma was excised and examined by a frozen section.

Between July 1999 and August 2001, 97 patients (64 females and 33 males, mean age; 56 +/- 14, range 19-88) underwent 100 focused, minimally invasive, MIBI guided parathyroidectomies (3 patients were operated on twice due to a residual second adenoma). Pre-operative blood levels of calcium and PTH were 11.5 +/- 0.8 mg/dl and 140 +/- 90 pg/ml, respectively. In 93 cases, an adenoma was identified and excised (mean weight, 600 mg, range, 100-4900). Mean operative time, including frozen section was 66 +/- 39 minutes. The patients were discharged on the same day or on POD 1 (mean calcium level 9 +/- 0.9 mg/dl) and had normal calcium levels at the follow-up tests. In 2 cases, the scan was falsely negative for adenoma (positive for other thyroid pathology), but the adenoma was successfully excised according to the sonographic localization (overall success rate in the primary procedure, 95%). In 3 cases, pathologically proven enlarged parathyroid was excised, as localized by the scan, but hypercalcemia relapsed. The patients were re-operated in a focused fashion and a residual second adenoma was found (N = 2), or underwent formal exploration for hyperplasia of the remaining 3 glands (N = 1). In 2 more cases, no parathyroid tissue was found in the specimen. However, consequently, calcium levels normalized after surgery (N = 1) and a successful focused re-operation was performed after relocalization (N = 1). There were no significant post-operative complications.

Focused MIBI guided parathyroidectomy is safe and efficient in most patients. Failures, which may be the results of erroneous diagnosis (hyperplasia vs. adenoma, 1%), residual additional adenoma (2%) or a false positive scan due to pathology in the thyroid gland (2%), can be treated safely and effectively in a second focused procedure.